From: Takashi Iwai <tiwai@suse.de> To: Jon Hunter <jonathanh@nvidia.com> Cc: Sameer Pujar <spujar@nvidia.com>, pierre-louis.bossart@linux.intel.com, perex@perex.cz, alsa-devel@alsa-project.org, thierry.reding@gmail.com, rlokhande@nvidia.com, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org Subject: Re: [PATCH] ALSA: hda/tegra: enable clock during probe Date: Fri, 25 Jan 2019 14:58:07 +0100 [thread overview] Message-ID: <s5hef90zvo0.wl-tiwai@suse.de> (raw) In-Reply-To: <b64f5d05-f352-7b46-d70d-3809aab8ddda@nvidia.com> On Fri, 25 Jan 2019 14:26:27 +0100, Jon Hunter wrote: > > > On 25/01/2019 12:40, Takashi Iwai wrote: > > On Fri, 25 Jan 2019 12:36:00 +0100, > > Jon Hunter wrote: > >> > >> > >> On 24/01/2019 19:08, Takashi Iwai wrote: > >>> On Thu, 24 Jan 2019 18:36:43 +0100, > >>> Sameer Pujar wrote: > >>>> > >>>> If CONFIG_PM is disabled or runtime PM calls are forbidden, the clocks > >>>> will not be ON. This could cause issue during probe, where hda init > >>>> setup is done. This patch checks whether runtime PM is enabled or not. > >>>> If disabled, clocks are enabled in probe() and disabled in remove() > >>>> > >>>> This patch does following minor changes as cleanup, > >>>> * return code check for pm_runtime_get_sync() to take care of failure > >>>> and exit gracefully. > >>>> * In remove path runtime PM is disabled before calling snd_card_free(). > >>>> * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check. > >>>> * runtime PM callbacks moved out of CONFIG_PM check > >>>> > >>>> Signed-off-by: Sameer Pujar <spujar@nvidia.com> > >>>> Reviewed-by: Ravindra Lokhande <rlokhande@nvidia.com> > >>>> Reviewed-by: Jon Hunter <jonathanh@nvidia.com> > >>> (snip) > >>>> @@ -555,6 +553,13 @@ static int hda_tegra_probe(struct platform_device *pdev) > >>>> if (!azx_has_pm_runtime(chip)) > >>>> pm_runtime_forbid(hda->dev); > >>>> > >>>> + /* explicit resume if runtime PM is disabled */ > >>>> + if (!pm_runtime_enabled(hda->dev)) { > >>>> + err = hda_tegra_runtime_resume(hda->dev); > >>>> + if (err) > >>>> + goto out_free; > >>>> + } > >>>> + > >>>> schedule_work(&hda->probe_work); > >>> > >>> Calling runtime_resume here is really confusing... > >> > >> Why? IMO it is better to have a single handler for resuming the device > >> and so if RPM is not enabled we call the handler directly. This is what > >> we have been advised to do in the past and do in other drivers. See ... > > > > The point is that we're not "resuming" anything there. It's in the > > early probe stage, and the device state is uninitialized, not really > > suspended. It'd end up with just calling the same helper > > (hda_tegra_enable_clocks()), though. > > Yes and you can make the same argument for every driver that calls > pm_runtime_get_sync() during probe to turn on clocks, handle resets, > etc, because at the end of the day the very first call to > pm_runtime_get_sync() invokes the runtime_resume callback, when we have > never been suspended. Although there are some magical pm_runtime_*() in some places, most of such pm_runtime_get_sync() is for the actual runtime PM management (to prevent the runtime suspend), while the code above is for explicitly setting up something for non-PM cases. And if pm_runtime_get_sync() is obviously superfluous, we should remove such calls. Really. > Yes at the end of the day it is the same and given that we have done > this elsewhere I think it is good to be consistent if/where we can. The code becomes less readable, and that's a good reason against it :) thanks, Takashi
WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de> To: Jon Hunter <jonathanh@nvidia.com> Cc: Sameer Pujar <spujar@nvidia.com>, <pierre-louis.bossart@linux.intel.com>, <perex@perex.cz>, <alsa-devel@alsa-project.org>, <thierry.reding@gmail.com>, <rlokhande@nvidia.com>, <linux-kernel@vger.kernel.org>, <linux-tegra@vger.kernel.org> Subject: Re: [PATCH] ALSA: hda/tegra: enable clock during probe Date: Fri, 25 Jan 2019 14:58:07 +0100 [thread overview] Message-ID: <s5hef90zvo0.wl-tiwai@suse.de> (raw) In-Reply-To: <b64f5d05-f352-7b46-d70d-3809aab8ddda@nvidia.com> On Fri, 25 Jan 2019 14:26:27 +0100, Jon Hunter wrote: > > > On 25/01/2019 12:40, Takashi Iwai wrote: > > On Fri, 25 Jan 2019 12:36:00 +0100, > > Jon Hunter wrote: > >> > >> > >> On 24/01/2019 19:08, Takashi Iwai wrote: > >>> On Thu, 24 Jan 2019 18:36:43 +0100, > >>> Sameer Pujar wrote: > >>>> > >>>> If CONFIG_PM is disabled or runtime PM calls are forbidden, the clocks > >>>> will not be ON. This could cause issue during probe, where hda init > >>>> setup is done. This patch checks whether runtime PM is enabled or not. > >>>> If disabled, clocks are enabled in probe() and disabled in remove() > >>>> > >>>> This patch does following minor changes as cleanup, > >>>> * return code check for pm_runtime_get_sync() to take care of failure > >>>> and exit gracefully. > >>>> * In remove path runtime PM is disabled before calling snd_card_free(). > >>>> * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check. > >>>> * runtime PM callbacks moved out of CONFIG_PM check > >>>> > >>>> Signed-off-by: Sameer Pujar <spujar@nvidia.com> > >>>> Reviewed-by: Ravindra Lokhande <rlokhande@nvidia.com> > >>>> Reviewed-by: Jon Hunter <jonathanh@nvidia.com> > >>> (snip) > >>>> @@ -555,6 +553,13 @@ static int hda_tegra_probe(struct platform_device *pdev) > >>>> if (!azx_has_pm_runtime(chip)) > >>>> pm_runtime_forbid(hda->dev); > >>>> > >>>> + /* explicit resume if runtime PM is disabled */ > >>>> + if (!pm_runtime_enabled(hda->dev)) { > >>>> + err = hda_tegra_runtime_resume(hda->dev); > >>>> + if (err) > >>>> + goto out_free; > >>>> + } > >>>> + > >>>> schedule_work(&hda->probe_work); > >>> > >>> Calling runtime_resume here is really confusing... > >> > >> Why? IMO it is better to have a single handler for resuming the device > >> and so if RPM is not enabled we call the handler directly. This is what > >> we have been advised to do in the past and do in other drivers. See ... > > > > The point is that we're not "resuming" anything there. It's in the > > early probe stage, and the device state is uninitialized, not really > > suspended. It'd end up with just calling the same helper > > (hda_tegra_enable_clocks()), though. > > Yes and you can make the same argument for every driver that calls > pm_runtime_get_sync() during probe to turn on clocks, handle resets, > etc, because at the end of the day the very first call to > pm_runtime_get_sync() invokes the runtime_resume callback, when we have > never been suspended. Although there are some magical pm_runtime_*() in some places, most of such pm_runtime_get_sync() is for the actual runtime PM management (to prevent the runtime suspend), while the code above is for explicitly setting up something for non-PM cases. And if pm_runtime_get_sync() is obviously superfluous, we should remove such calls. Really. > Yes at the end of the day it is the same and given that we have done > this elsewhere I think it is good to be consistent if/where we can. The code becomes less readable, and that's a good reason against it :) thanks, Takashi
next prev parent reply other threads:[~2019-01-25 13:58 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-24 17:36 [PATCH] ALSA: hda/tegra: enable clock during probe Sameer Pujar 2019-01-24 17:36 ` Sameer Pujar 2019-01-24 19:08 ` Takashi Iwai 2019-01-24 19:08 ` Takashi Iwai 2019-01-25 7:08 ` Sameer Pujar 2019-01-25 7:08 ` Sameer Pujar 2019-01-25 11:36 ` Jon Hunter 2019-01-25 11:36 ` Jon Hunter 2019-01-25 12:40 ` Takashi Iwai 2019-01-25 12:40 ` Takashi Iwai 2019-01-25 13:26 ` Jon Hunter 2019-01-25 13:26 ` Jon Hunter 2019-01-25 13:58 ` Takashi Iwai [this message] 2019-01-25 13:58 ` Takashi Iwai 2019-01-25 14:04 ` Jon Hunter 2019-01-25 14:04 ` Jon Hunter 2019-01-28 6:06 ` Sameer Pujar 2019-01-28 6:06 ` Sameer Pujar 2019-01-30 9:35 ` Jon Hunter 2019-01-30 9:35 ` Jon Hunter 2019-01-30 10:39 ` Takashi Iwai 2019-01-30 10:39 ` Takashi Iwai 2019-01-30 10:56 ` Sameer Pujar 2019-01-30 10:56 ` Sameer Pujar 2019-01-30 12:24 ` Jon Hunter 2019-01-30 12:24 ` Jon Hunter
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